[BioC] GSEA with one class metaanalysis
Mark W Kimpel
mwkimpel at gmail.com
Fri Mar 2 18:04:09 CET 2007
I am in the process of performing a meta-analysis on multiple MA studies
run on several platforms and several species. Although I realize there
are probably other ways to approach the data, my collaborators have
chosen to use Cohen's D-statistic to summarize their data.
I would like to use GSEA to look for over-represented groups or pathways
in the data, but what I will end up with is essentially a one-class
experiment. In other words, I would like to identify groups whose
summary D-statistic (I recognize from the recent literature that there
is more than one summary method available) is different from zero.
From what I have read, the GSEA method is usually used to evaluate 2
class data, the GSA method of Tibshurani can be used to evaluate
multi-class data, but can either method be easily adapted to evaluate
one class data? It would seem theoretically reasonable, but I don't know
if I would have to modify one of the packages or if one already provides
for this.
And, while I'm at it, I will also want to look for individual genes
whose average D-statistic is different from zero. I am advocating using
a t-test with n=number of experiments with corresponding degrees of
freedom, whereas others are advocating using a z-test because the
D-statistics are summarizing many underlying individual statistics.
Help with these questions would be deeply appreciated.
Mark
--
Mark W. Kimpel MD
Neuroinformatics
Department of Psychiatry
Indiana University School of Medicine
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